This invention relates to an apparatus, and a method, for setting a Doppler sample point in a ultrasonic tomograph. More particularly, this invention makes it possible to automatically set a desired Doppler sample point.
A conventional ultrasonic tomograph of this kind comprises a probe for transmitting and receiving ultrasonic waves into and from an object, a ultrasonic wave transmission/reception unit for transmitting the ultrasonic waves into a diagnostic portion of the object by driving the probe and inputting and processing reflected echo signals received by the probe, a display unit for inputting reception signals from the ultrasonic wave transmission/reception unit and displaying a ultrasonic tomogram of the diagnostic portion, a Doppler sample point designation unit for designating and displaying a Doppler sample point for a bloodstream portion of the ultrasonic tomogram displayed on the display unit, Doppler operation means for acquiring flow velocity information of the bloodstream at the Doppler sample point designated by the Doppler sample point designation unit, and a control circuit unit for controlling the operation of each of these constituent units. This ultrasonic tomograph achieves a Doppler function capable of observing the bloodstream flow velocity at an arbitrary point on the ultrasonic tomogram of the diagnostic portion and also a color flow mapping function of superposing the bloodstream movement, that includes the flowing direction of the bloodstream, the flow velocity and the change with time, at the diagnostic portion, with the ultrasonic tomogram, and displaying the movement in color. This technology is described, for example, in Navin C. Nanda, xe2x80x9cTextbook of Color Doppler Echocardiographyxe2x80x9d, p7-17 (1989).
In the conventional ultrasonic tomograph described above, the Doppler sample point is designated for the bloodstream portion of the ultrasonic tomogram displayed on the display unit by moving manually a Doppler sample setting mark to a position of a region of interest, at which the bloodstream exists, by moving means such as a track ball. The setting and diagnostic procedures in this case are as follows.
(1) The ultrasonic tomogram is observed.
(2) The movement of the bloodstream is observed by superposing color bloodstream information on the ultrasonic tomogram.
(3) When the Doppler sample point setting mark is set to the blood vessel the Doppler image of which is desired to be displayed, the Doppler image at that point is displayed, and the Doppler image is observed.
In this instance, the observation mode is switched in the procedure (3) to the Doppler image observation mode. However, the display position of the Doppler sample point setting mark exists at the center on the ultrasonic tomogram under the initial state and thereafter changes to the position that is displayed previously. Thereafter, an operator decides the region of interest of the Doppler image on the basis of the ultrasonic tomogram and the color bloodstream image, and then moves the position of the Doppler sample point by moving means such as the track ball. Even after the Doppler sample point is moved into the region of interest, the operator has to move and decide manually the position that is appropriate for the observation of the Doppler information inside the region of interest, at which the Doppler image can be displayed satisfactorily, while watching the ultrasonic tomogram, the color bloodstream image and the display condition of the Doppler image.
However, in such a conventional ultrasonic tomograph, the Doppler sample point for the bloodstream portion of the ultrasonic tomogram displayed on the display unit is designated by manually moving the Doppler point setting mark by using the moving means such as the track ball to the position at which the bloodstream exists on the region of interest, on the basis of the color bloodstream information displayed in superposition with the ultrasonic tomogram. Therefore, it needs time to move the Doppler sample point setting mark to the region of interest on the display image, or to set it to the position inside the region of interest at which the Doppler information can be observed satisfactorily.
In consideration of these problems, it is an object of the present invention to provide a ultrasonic tomograph capable of setting either automatically or semi-automatically the Doppler sample point to the bloodstream portion of the ultrasonic tomogram displayed as the image.
According to one aspect of the present invention, there are provided a sample point setting apparatus in a ultrasonic tomograph, and a method therefor, capable of setting a desired Doppler sample point, either automatically or semi-automatically, on the basis of bloodstream information, by transmitting and receiving ultrasonic waves to and from an object through a probe so as to form a ultrasonic tomogram, displaying it on a display unit, generating blood stream information by a Doppler operation unit, displaying it in superposition with the ultrasonic tomogram and moreover, designating a desired condition.